It is well known to utilize mechanical heart valves, such as the ball check valve, and natural tissue cardiac valves to replace defective aortic and mitral valves in human patients. One type of natural tissue heart valve typically employs a porcine valve for implantation in a human, as they are very similar to human valves of appropriate size and generally are easy to procure. Typically, the porcine valve is fixed by chemically treating it, such as with an appropriate glutaraldehyde solution. The treated porcine valve further may be mounted into a stent to support the valve at a fixed position.
A stent typically is formed of a resilient material, such as a plastic (e.g., DELRIN). Examples of various stent structures are disclosed in U.S. Pat. No. 3,983,581, U.S. Pat. No. 4,035,849. The stent usually is covered with a fabric material, such as DACRON or a suitable textile material. The fabric material provides structure for securing the valve relative to the stent. The stented heart valve prosthesis may be implanted into a patient for a heart valve replacement.
In order to surgically implant a heart valve into a patient, the patient typically is placed on cardiopulmonary bypass during a complicated, but common, open chest procedure. In certain situations, an individual requiring a heart valve replacement may be sufficiently ill, such that placing the individual on cardiopulmonary bypass may pose too great a risk. Such individuals may correspond to a class of patients who may have a non-functioning pulmonary valve or severe aortic valve insufficiency. In particular, older patients having a deficient aortic valve may be too ill to survive conventional open-heart surgery.
Another class of individuals may be suffering from vascular degeneration associated with the lower extremities. Such degeneration may include inoperative or otherwise ineffective venous valves resulting in one or more undesirable indications.
These and other conditions would benefit from an improved valvular prosthesis that may be implanted by a less invasive and/or less time-consuming implantation procedure.